Each unit of intermodal equipment must identify the intermodal equipment provider (IEP) by its legal or trade name and USDOT number. Section 390.21(g)(4) gives an IEP four options for identifying its IME, which include:

Marking the identification on the curb side of the item of equipment. The marking must be in letters that contrast sharply in color with the background on which the letters are placed. The identification code must be readily legible, during daylight hours, from a distance of 50 feet (15.24 meters) while the CMV is stationary. It must be kept and maintained in a manner that retains this legibility

Placing the identification marking on a label placed upon the curb side of the item of equipment. The label must be readily visible and legible to an inspection official during daylight hours when the vehicle is stationary. The label must be a color that contrasts sharply with the background on which it is placed, and the letters must also contrast sharply in color with the background of the label. The label must be kept and maintained in a manner that retains this legibility

Including the USDOT number of the IEP, as well as the vehicle identification number (VIN) and 4-character Standard Carrier Alpha Code (SCAC) and 6-digit unique identifying number on the interchange agreement so that it is clearly identifiable to an inspection official

Placing the identification information on a document placed in a weather-tight compartment affixed to the frame of the item of IME. The color of the letters used in the document must contrast sharply in color with the background of the document. The document must include additional information to identify the specific item of IME (such as the VIN and 4-character SCAC and 6-digit unique identifying number)

The marking information must be kept in an electronic database as stated in § 390.21(g)(4)(v). The electronic database must be available via real-time internet or through telephonic access. The system the industry uses to mark their intermodal equipment is GIER: